This operator can help select your international flights, but you'll have to book them yourself help
Fly to/from Abeid Amani Karume Airport (ZNZ - Check price) on Zanzibar. Or fly to/from Dar es Salaam (DAR - Check price) . There are daily ferries between Dar es Salaam and Zanzibar.
A transfer from and back to the airport is included
Additional accommodation before and at the end of the tour can be arranged for an extra cost
We did a 4-day safari, covering Tarangire, Serengeti, Ngorongoro, and Manyara. I would say that 4 days is more than enough, beyond that it becomes tiring. The guides were always kind and helpful. The lodges booked were always well organized...